Engineering an Electrode–Electrolyte Interphase for Ultrastable Aqueous Aluminium–Air Battery

Abstract

ABSTRACT Aluminium–air battery (Al–air battery) stands at forefront of next‐generation energy storage technologies; however, their practical implementation is critically hindered by uncontrolled hydrogen evolution reaction (HER) and rapid anode degradation in alkaline environment. Herein, we explored multifunctional boric acid (BA) as an additive that orchestrates electrolyte–electrode interactions by simultaneously functioning as pH buffer, hydrogen‐bond regulator and Al 3+ solvation shell modulator. This synergistic effect driven the formation of boron‐rich, self‐protective aluminium oxide layer, as elucidated through scanning electrochemical microscopy (SECM) investigations, in‐situ electrochemical Raman spectroscopy and x‐ray photoelectron spectroscopy (XPS) analysis. Thus, introduction of BA inhibited the Al corrosion rate by 82.7% and enabled Al–air battery stability upto 302 h over 906 cycles. HER suppression was substantiated by molecular dynamic simulations and SECM‐derived kinetic analysis, where heterogeneous electron transfer rate constant decreased from 9.94 * 10 −4  cm s −1 in 1 M KOH to 8.80 * 10 −4  cm s −1 upon addition of boric acid. The optimized Al–air battery successfully powered a panel of 38 blue LEDs for 28.5 h, underscoring its practical applicability.